1. Field of the Invention
The present invention relates generally to subterranean drilling for fluid production, and more particularly but not by way of limitation, to an apparatus and method for increasing production through the use of elastic wave stimulation.
2. Discussion
A well known problem associated with oil and gas production is the general reduction over time in the amount that can be extracted from a field. Typically, the natural pressure in a subterranean oil field is sufficient to result in no more than about ten percent of the oil contained in the formation. The residual amount is difficult to produce because of its very low mobility. Accordingly, recovery of these residual amounts is of great concern to the oil and gas industry.
The oil and gas industry has painstakingly attempted to develop efficient and effective methods for enhanced oil recovery (EOR). Historically, the prior art is replete with methodologies designed to augment oil and gas production, including water, steam and gas injection, chemical surfactants, hydraulic and explosive fracturing, and layer burning. Recent scientific observations of earthquake activity, however, show a correlation between seismic waves generated by the earthquake and nearby oil and gas production.
Scientific experimentation to duplicate the effects of seismic waves produced by an earthquake have been successful in stimulating the production of oil and gas fields. There are promising new technologies being developed which produce elastic wave energy for well stimulation. The effect of elastic wave energy has been proven to alter the permeability of subterranean oil formations, which has an excitation effect and can appreciably increase the mobility of the oil.
An elastic wave energy approach to well stimulation avoids the well known disadvantages associated with the historically known methods, which were largely undesirable because they were costly, required shutting in production, and created harmful ecological consequences.
New technologies being developed for elastic wave stimulation of oil are currently focused on ultrasonic wave generation and on vibroseis-type wave generation. However, there is a need for an improved approach to generating elastic wave energy, preferably one that employs well known drilling methodologies to provide an inexpensive yet effective and reliable approach. Furthermore, there is a need for an improved approach that is capable of stimulating more than one well at once in order to reduce the expense and complexity of the procedure.